Curious what everyone's thoughts are on having business logic in the front end, validation in the back is fine but should there be an aversion to making something complex in javascript? Gut feeling is shouldn't but I don't have the experience to really figure out why.

I think the philosophy I had heard was that the business logic sometimes has to be on the back end, and you don't want to have to wonder where it is, so since some of it has to be there put all of it there. I think the issue is that the webapp model doesn't really have a front-end/back-end split any more, the backend is in some ways more like the database, with the front end doing what the back end used to.

Except, not always, the backend still does plenty of stuff that is not just like being a database. So, inevitably, it is increasing complexity to split this stuff between the client and server. Which means more developers are needed for the same amount of functionality, and also the code gets into a Ball of Mud faster. The question is whether or not this is an acceptable tradeoff, when the alternative is to have a laggier interface. I suspect it is not, but perhaps I am just biased. Certainly it is a tradeoff that is being widely accepted.

That makes sense about wondering where something is because thats one of the things I deal with when debugging. But that's also a problem in the backend, I've run into code that is split into multiple places with different versions of the same program all being used simultaneously.

Is it usually faster to do some logic like sorting and calculations in the clients browser than to do it on the server before sending the information? If so then I could see a reason to move some logic out and I may do it if the gain is appreciable.